yml_to_tsv.rb

require 'yaml'
require 'csv'

def hashs_to_array(hashs)
  array = []
  hashs.each do |hash|
    array << hash.keys if array == []
    array << hash.values
  end
  array
end

hashs = YAML.load(File.read(ARGV[0]))
array = hashs_to_array hashs

File.open(ARGV[1], 'w') do |file|
  file.puts array.map(&:to_csv)
end